Why can a single chlorine atom released from a CFC destroy many ozone molecules rather than just one?
Environmental impacts · EPA 608 Core. The correct answer, and the reasoning behind it.
How CFCs and HCFCs destroy stratospheric ozone, and what that does to health and the environment.
The question
Why can a single chlorine atom released from a CFC destroy many ozone molecules rather than just one?
- It splits into several smaller atoms after each reaction
- It combines with fluorine to form new chlorine
- It is freed again after each reaction and keeps goingCorrect answer
- It turns ozone into more CFC molecules
Why “It is freed again after each reaction and keeps going” is correct
Chlorine acts as a catalyst. It breaks an ozone molecule, and through a follow-up reaction the chlorine atom is released again to attack more ozone. One atom can repeat this cycle many times before it is finally tied up in a stable compound.
Source: EPA: Test Topics
Why the other answers are wrong
- It splits into several smaller atoms after each reaction — An atom does not split into more chlorine atoms in these reactions.
- It combines with fluorine to form new chlorine — Chlorine is not created from fluorine; the same chlorine atom is recycled.
- It turns ozone into more CFC molecules — Ozone is turned into ordinary oxygen, not into CFCs.
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